Severe storms brought heavy rain and flash flooding to communities across the Georgia-Tennessee border area late on Wednesday and into Thursday morning that forced dozens of rescues, despite the hazardous conditions making evacuations and efforts to save people difficult.

McCaysville, in north central Georgia, was deluged with up to five inches (13cm) of rain by Thursday morning, triggering life-threatening flash flooding, the National Weather Service (NWS) said. The town lies just across the Toccoa River from Copperhill, Tennessee.

The NWS issued a flash flood warning for the area until mid-morning Thursday, saying: “This is a particularly dangerous situation. Seek higher ground now! Life threatening flash flooding of low water crossings, small creeks and streams, urban areas, highways, streets and underpasses.

“Turn around, don’t drown when encountering flooded roads. Most flood deaths occur in vehicles,” it added.

Georgia’s governor, Brian Kemp, announced on Thursday morning that the state’s emergency management agency was leading a “multi-agency response … using both aviation and boat assets, as well as local counties and Tennessee first responders.”

More than 30 people had been rescued by boats by mid-morning, McCaysville police chief, Michael Earley, said.

“I’ve never seen flooding like this in my life,” Earley said, local TV station WSMV reported, adding that the water in some areas was six to seven feet high.

“Anyone who’s willing to help, we’re asking for help,” he added. One local report later in the morning informally put the number of rescues by water above 50 so far.

Robert Poole, a Fannin county emergency management spokesperson, also told WSMV that one rescue effort involved a person who was trapped in his car.

“We currently have a crew looking for a vehicle. A gentleman called in, said he was swept away in his car down a creek,” Poole said early on Thursday morning, adding: “We lost communications with him. They have, I guess, an address now and the gentleman is still trapped in the vehicle, so they’re trying to make their way to him and safely get him out of the vehicle.”

Poole added: “We … already had our resources kind of stretched thin from several structure fires that happened, kind of just all at one time when the lightning moved in … And then as the rain continued to fall, these water rescues followed the structure fires.”

“Please do not let the rain stopping give you a false sense of security,” the agency said on social media, adding: “Floodwaters remain extremely dangerous, and conditions can continue to worsen even after the rain has stopped.”

It also issued a boil water advisory for McCaysville.

Game wardens with the Georgia department of natural resources are also assisting state and local first responders with search-and-rescue operations in Fannin and Murray counties, county officials said on Thursday.

School closures were announced on Thursday for students at Fannin and Gilmer county schools due to hazardous road conditions.

Residents of Copperhill, Tennessee, were also affected by the flash flooding. At 3am ET on Thursday, city officials issued evacuation warnings for some.

The Associated Press contributed reporting